Grinding wheel dresser



3 Sheets-Sheet l D` F. PRICE ETAL GRINDING WHEEL DRESSER Filed June' e, 1940 Feb. 1, 1944.

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Filed June 6, 1940 3 Sheets-Sheet 3 3mm-mors Lvo/VALL F. Pue/cs HAnoLn E. .BALS/651e f f M/LBURN A H LLENGREEN Gttorneg Patented Feb. 1, 1944 GRINDING WHEEL muessen Donald F. Price, Harold E. Balsiger, and Milburn A. Hollengreen, Waynesboro, Pa., assignors to Landis Tool Company, Waynesboro, Pa.

Application June 6, 1940, Serial No. 339,174

13 Claims.

Oui` invention relates to wheel dressing mechanisms Vfor grinding machines, particularly for that type of machine having a plurality of irregularly spaced grinding Wheels mounted on a spindle between the bearings thereof.

An object of our invention is to provide means for shifting a dressing device toward or away from the grinding wheels under conditions where a cam or contour bar will not function satisfactorily, viz., where two wheels of different diameters'are spaced apart a distance less than the difference in radius between the wheels.

A further object is to provide means for shifting said dressing device toward and from the Wheels only when said device has been positioned relative to the proper wheel.

A further object is to provide a dresser movable transversely in either direction during traverse in one direction.

In supporting Work for a grinding operation on a machine of the type referred to herein, steady rests on the center bearings were thought suicient to prevent distortion. However, it has been determined that the restson-the two center bearings tend to distort work in opposition to the distortion caused by the feed of the grinding wheel on the work pieces. If ground with straight faced Wheels while so distorted the finished Work'piece will consist of tapered portions instead of straight portions.

A further object therefore is to dress each of a. plurality of grinding wheels with a predeterf mined taper to compensate for distortion in the work during grinding.

Our mechanism for dressing closely spaced grinding wheels of different diameters consists of a mechanism or mechanisms mounted on the Wheel support and movable therewith. Said mechanism consists of a hydraulically oscillated finger which projects into operative relation with the dresser as the dresser carriage passes across the position where said mechanism is located. Where more than one set of closely spaced wheels is used on a machine, a mechanism of this type can be located in position'relative to each set of wheels; or a plurality of fingers may be positioned, one to each set of wheels, with a single actuating means for all of them. Available dressers for closely spaced wheels have the longitudinal and transverse movements of the tool rigidly interlocked. One of the features of our invention is that the tool may be shifted transversely in either direction while the carriage moves continuously in one direction.

Figure 1 is an end elevation of our device partly in section.

Figure 2 is a partial sectional elevation-show- I ing an optional form of our invention.

Figure 3 is a plan View showing the relative positions of a pair of control switches and the means for actuating same.

Figure 4 is a rear elevation partly in section. Figure 5 is a plan view in conjunction with a piping and wiring diagram.

In the drawings, numeral I0 indicates a portion of a wheel support or base, on which are mounted a plurality of grinding vwheels 40 to 44 inclusive,-II a slide base secured to said wheel support and having ways I2 and I3 running' transversely of the direction of movement'of saidA support. A carriage I4 is slidably mounted on said slide base and may be reciprocated thereon by means of a, motor consisting of a cylinder I5 attached to said slide base and having a piston I6 slidably mounted therein; a piston rod II on said piston extends thru one end of said cylinder and is attached to carriage I4 by means of bracket I8.

A tool slide 20, similar to that disclosed in Ott et al. application, Serial No. 220,776, filed July 22, 1938, which became Patent No. 2,248,463, July 8, 1941, is slidably mounted on said carriage for movement transversely thereof. A tool holder 2| having a diamond tool 22 inserted therein is supported in said tool slide, and may be adjusted manually toward and from a grinding wheel along withv said tool slide by means of a handy wheel 23 as shown in said above mentioned appli!y cation. Said hand wheel may be actuated automatically at the reversal of movement of carriage I4 by means of a piston actuated pawl,y (not shown) in cylinder 25.

Mechanism for shifting said slide rapidly from a position for dressing a Wheel of one diameter to position for dressing a vwheel of a smaller diameter, consists of a cylinder 30 mounted lon slide base Il between the Ways I2 and I3. Piston 3l, reciprocably mounted in said cylinder, has a toothed portion 32 intermediate the ends thereof` dental jumping of the diamond tool toward the grinding wheel. Said follower 55 is held in engagement with said cams by a back lash mechanism consisting of cylinder 50 formed inv the lower portion of a housing which includes the cylinder 25. A piston 5l in cylinder 80 extends beyond the end of said cylinder and has a ball bearing roller 52. mounted in the outer end thereof. Said roller engages a guide surface 88 on the side of slide base Il.` This allows carriage |4 to follow ways I2 uniniiuenced by back lash pressure. Fluid under pressure is directed into said cylinder direct from the source of supply. The end of cylinder 60 is enlarged to receive a coil of tubing 85, one end of which is open to said cylinder, the other end being connected to a check valve 65 thru which fluid under low pressure passes thru additional tubing (not shown) to the various guide surfaces to provide a supply of lubricant therefor.

In Figure 2 is shown an optional method for actuating a series of tool slide positioning ngers. Instead of having a separate piston and cylinder for each linger, a single motor consisting of a piston 'I0 in cylinder rotates shaft 12 by means of rack teeth 18 on said piston engaging pinion '|4 on said shaft. A series of ngers I5 suitably spaced are secured to said shaft and rotate therewith.

It will be noted that the linger 85 or any other finger is located between the cams which guide the dresser across the closely spaced wheels of different diameters. The function of the finger is to lift the follower from one cam to the other, and in so doing said finger moves to a position flush with the cam to which the follower is moving so that said follower may move smoothly off of the nger and on to the cam.

Means for controlling the rapid transverse movement of the dresser and the rapid and slow traverse movements consists of a pair of switches 80 and 8| mounted on the wheel support adjacent slide base Said switches are actuated by arms 82 and 88 respectively. Arm 82 is secured to one end of a shaft 84 and arm 83 is secured to one end of a shaft 85. Said shafts are rotatably mounted in a support bracket 86. At the opposite end of shaft 84 is secured an arm 81 having a roller 88 for successively engaging a series of cams 88. Said cams are attached to carriage I4 by means of a plate 90 suspended therefrom. An arm 8| is secured to shaft 85 on the end thereof opposite from arm 88, and a roller 92 on. said arm successively engages a series of cams 93. Said cams also are mounted on plate 90.

Switch 80 is a normally open switch and it serves to control the transverse movement of theidiamond tool. Switch 8| is also normally open and functions when closed to effect a slow down of the movement of carriage |4 as the diamond tool 22 is passing across a grinding wheel.

A third switch |00 may be mounted in any suitable position to engage carriage |4 or some member movable therewith when lsaid carriage reachesthe end of its movement in one direction.

Operation Fluid under pressure for operating our device is supplied by a pump ||0 thru a line From said line it is directed thru branch lines to each of the several mechanisms. To initiate operation of our device, theoperator presses either of the start switches |20 or |2|, one of which may be located at the front of the machine and the other at the rear, The circuit thus closed energizes relay |22 closing the normally open contacts |221 and |222. Contact |221 completes a holding circuit which includes a normally closed limit switch |00 and a pair of stop switches |28 and |24 in series. Said stop switches may be located at widely spaced positions on the machine; for example, one at the front and one at the rear. Closing contact |222 completes a circuit to energize a solenoid |80 which then shifts a valve |8| against the action ofa spring |82. Fluid under pressure is directed to said valve from line thru branch line |88, valve |84 and line |85. Solenoid |85 being energized, valve |8| is in the extreme right hand position. Fluid under pressure in-line |85 is therefore directed thru line |85 to the left end of a traverse cylinder l5 shifting piston I8 therein to the right and with it the carriage |4. Fluidvfrom line |88 is also directed to cylinder 25 to rotate hand wheel 28 and feed diamond tool 22 as described in the above mentioned application. Fluid under constant pressure from line is also directed into cylinder 50 where by urging the roller 52 constant pressure from line is also directed erted against the tool slide 20 to withdraw same and thereby hold follower 'rmly in contact withany of the cams 50 to 54 inclusive, and to shift the diamond tool 22 from forward position to rearward position when necessary.

'I'he dressing traverse starts from the left hand position. Follower 55 is in contact with the inclined portion of cam 50 and diamond tool 22 is therefore out of line with wheel 40. Switch 80 is held in closed position at this time by one of the cams 88. Switch 80 completes a circuit to energize solenoid |40. When so energized said solenoid holds a valve |4| in the right hand position against spring |42. Fluid nom pressure line is directed to said valve thru a line |48.

When said valve is in the right hand position uid is directed thru a line |44 to a line |50 which in turn carries said :duid to one or more cylinders 80. Piston 8| in said cylinder acting thru the mechanism described above, moves finger 85 to a position where the face thereof is liiiush'with the face of cam 50. As the diamond tool 22 passes across wheel 40, follower 55 moves onto finger 85.

At the same time, the cam 88 releases switch 80 and solenoid |40 is deenergized. Valve |4| is shifted by spring |42 to the left hand position and fluid from line |48 is directed thru line |46 to line |5| which carries said fluid to the opposite end of said one or more cylinders 80. Piston 8| in said cylinder moves to shift linger 85 from a position flush with cam 50 to a positionllush with cam 5|. Fluid under pressure in cylinder is thuspermitted to shift tool slide 20 rearwardly until follower 55 is in position to engage cam 5|. When fluid under pressure is directed to one side or the other of cylinder 80, it is also directed thru lines |60 or |0| to one end or the other of the pressure actuated valve |84. Bald valveissimilarinmostrespectstothatshownin pass slow speed valve |16.

copending application Serial No. 138,245. led Apru 21, 1937. is directed against a portion'of small cross section |62. The rate of movement of said valve is controlled by the action of an intermediate surface |63 on said valve. When fluid under pressure is directed against the small portion-at one end of the valve, the intermediate 'surface at the other end thereof Aacts on a body of uid expelling it rst thru a free line |68, and then thru a passage |65 having a throttle valve |61 therein, to the intermediate surface at the opposite end Thefiuid for shifting said valve contact with follower 55 and shifts same from the of said valve. Throttle-valve |61 determines the h rate of movement of valve |34. Said valve moves rapidly until the -free exhaust line |68 is closed thereby. At the same said valve breaks the connection between lines |33 and |35. A slot |69 thru the center land |10 connects line |35 with an exhaust line 1.31 so that both ends of cylinder I are open to exhaust pressure. The movement of valve |34 is timed to prevent traverse movement while diamond 22 -is moving inV or out. At the same time that the valve covers exhaust line |68, slet |69 passes across the end of line |35 connecting said line with exhaust passage |31. Thereafter, valve |34 moves rapidly on until lines |33 and |35 are again connected and the dressing traverse is resumed.

Carriage I4 and diamond tool 22 move at a speed suitable for dressing as said tool engageswheel 4|. Exhaust fluid from the right hand end of cylinder I5 passes thru line |38, throttle valves and |16 to traverse reversing valve |3|^from which it is exhausted. Valve |15 is set for the rapid movement of the dresser between wheels. Valve |16 is set for the slow traverse of thel dresser across a wheel. The traverse speed is selected by one of a series of cams 89 actuating a, limit switch 8|. These cams are so positioned that they actu-- ate switch 8| during the passage of the diamond tool 22 across the face of a grinding wheel. When switch 8| is closed, solenoid 11 shifts bypass valve time another portion of p |18 to the right against a spring |19. Normally,

said valve connects passages I 80 and |8| to bysaid solenoid the passage offluid thru said valve is stopped and it passes instead thru' said slow a slow traverse. As soon as the diamond passes oif the face of the wheel, switch 8| is released, solenoid |11 deenergized, and valve |18 shifted by spring |19 to the position shown in Figure 5. Inthis position of the valve, luid under pressure is again bypassed around valve |16 and the traverse speed. increased in proportion to the ow for which valve |15)l is adjusted to more rapidly bring the dressing tool to the next Wheel.

When carriage |4 reaches the end of its movement toward the right it engages a limit switch |00. Said switch is normally closed and therefore the circuit therethru is broken upon engagement of said carriage therewith. Breaking said circuit deenergizes relay |22 and thru Contact |222 deenergizes solenoid |30. Spring |32 shifts valve |3I to -the left to direct fluid under pressure from line |35 thru line |38 to the right hand end ofcylinder l5 to move carriage |4`to the left. The speed control for the dressing traverse and the traverse between wheels is the same as dej' When shifted by switch 80. Solenoid |40 is energized and shifts valve |4| to the right to direct uid under pressure from line |43 thru lines |44 and |50 to cylinder 30. Finger 35 between cams 53 and 54 is in face of cam 54 to that of cam 53. As described above, the traverse movement is stopped during the shifting of said linger. Diamond tool 22 is thus moved transversely into'contact with grinding wheel 43. Then the traverse movement is resumed. After the diamond tool hasmade the return pass over wheel 40 it is moved a short distance farther. during .which follower 55 follows the inclined portion of cam 50 and said diamond tool is withdrawn a short distance in a transverse direction. Said diamond tool remains in this position until the initiation of another dressing operation. The diamond starting position at any time before the carriage I4 reaches the end of its stroke from left to right. This may be accomplished by pressing either of the'stop switches |23 or |24. Pushing either of these switches has the same 'eifect' as the opera'- tion of switch |00 by carriage I4 described above.

As the diamond moves from one wheel to another, switch is depressed and released alternately by the cams 93, and thus said diamond may be shifted transversely either toward or away from the grinding wheels as it traverses them in one direction, l

It has been found that during grinding a plue,

-tions ground. In order to correct this condition,

separate adjustable cams 50 to 54 inclusive are used to guide the dressing tool 22 across each wheel. Each of these cams may be adjusted to cause the tool 22 to dress a tapered surface on each wheel, the degree of taper corresponding to v theamount of distortion occurring at each s urface. Adjustment of said ca-ms may be utilized to maintain a ixed relation between the surfaces of the various Wheels. If a particularwheel is grinding under or over size, the corresponding cam may be adjusted to guide the tool 22 so as to takes iight or heavy eut. Likewise, if it is desired to make a change in size of a certain por. tion, the change may be eiected by adjusting the corresponding cam as described above.

What is claimed is:

1. A mechanism for dressing a plurality of spaced wheels comprising a base forY rotatably supporting said Wheels, a'dressing tool slidably mounted for movement longitudinally and transversely of said wheels, a mechanism mounted independently of said dressing tool and operable for eecting said transverse `movement of said tool, and means for initiating operation of said mechanism only when said tool has been moved longitudinallyfinto operative relation therewith.

2.' A mechanism for dressing a plurality of spaced wheels comprising a base for rotatably versely of said wheels, 4a mechanism mounted independently'of said dressing tool for effecting said transverse movement of said tool, vand meansv operable automatically for actuating said mechanism in response to the longitudinal movement of said dresser into operative -relation with said mechanism.

tool may be returned to transverse movement of said tool including a dresser shifting nger and a motor for actuating same, and automatic means for actuating 'said i mechanism in response to the longitudinal movement of said dresser into operative relation with said mechanism.

4. A mechanism for dressing a plurality of spaced wheels comprising a base for rotatably supporting said wheels, a dressing tool slidably mounted for movement longitudinally and transversely of said wheels, a mechanism mounted in.

fixed relation to said wheels for effecting said transverse movement of said tool including a dresser shifting finger and a motor for actuating same, and a mechanism operable in response to longitudinal movement of said dresser into a predetermined position for initiatingoperation of said motor.

5. A mechanism for dressing a plurality of spaced wheels comprising a base for rotatably supporting said wheels, a dressing tool slidably mounted on said base for movement longitudinally and transversely of said wheels, a mechanism mounted in fixed relation to said wheels for effecting said transverse movement of said tool, automatic means including a control device for actuating lsaid mechanism in response to the longitudinal movement of said dresser into operative relation with said mechanism, and for resetting said mechanism and said dresser in response to longitudinal movement away from said operative relation in either direction.

6. A mechanism for dressing a plurality of spaced wheels, comprising a base for rotatably supporting said wheels, a dressing tool slidably mounted for movement longitudinally and transversely of said wheels, mechanisms mounted in fixed relation to said wheels for effecting said transverse movement of said tool at predetermined points in said longitudinal movement, including a plurality of dresser shifting ngers, and a motor for actuating each of said ngers, and means operable automatically in response to said longitudinal movement for actuating said mechanisms. l

7. A mechanism for dressinga plurality of spaced wheels, comprising a base for rotatably supporting said wheels, a dressing tool slidably mounted for movement longitudinally and transversely of said wheels, mechanisms mounted in xed relation to said wheels for effecting said transverse movement of said tool at predetermined points in said longitudinal movement, including a plurality of dresser 'shifting fingers, and a motor operable automatically in response to said longitudinal movement for actuating said mechanisms.

8. A mechanism for dressing a plurality of grinding wheels comprising a base member for rotatably supporting said wheels, a dressing tool slidably mounted for movement longitudinally and transversely of said base, means for guiding said tool and for compensating for distortion of the work during grinding including a series of adjustable cams corresponding to the wheels to be dresssed, one or more of said cams being adjusted so as to cause a tapered surface to be dressed on the corresponding wheel, the degree of taper corresponding to the amount of deformation in that portion of the work during the 10. A device for dressing a grinding operation.

9. A device 'for dressing a'plurality of grinding wheels including a base, a dressing tool slidably mounted for movement longitudinally and transversely of said base, a series of cam surfaces for guiding said dressing tool across the face' of each of said wheels, a follower on said dressing tool, means for urging said, follower against said cams, means for lifting said follower and said dresser transversely from one cam to another, and means including a control device for initiating actuation of said lifting means automatically in either direction during said longitudinal movement in one direction.

plurality of grinding wheels some of which are closely spaced and others of which are widely spaced, including a base, a dressing tool slidably mounted for movement longitudinally and transversely of said base, a series of cams for guiding said dressing tool across the face of e'ach of said wheels, a follower on said dressing tool, means for urging said follower against said cams, means for shifting said follower and said dresser transversely from one cam to another including a rotatable shaft, means on said shaft for engaging said follower,

ment in one direction.

l1. A device for dressing a plurality of grinding wheels including a base, a dressing tool slidably mounted for movement longitudinally and transmeans for lifting sald follower and said dresser transversely from member operable in response to said longitudinal movement for initiating said transverse movement in one direction and operable upon further longitudinal movement in the same direction for initiating said transverse movement in the opposite direction.

` 12. A mechanism for dressing a plurality of grinding wheels comprising a base member for rotatably supporting said wheels, a dressing tool slidably mounted for movement on said base, mechanisms` for effecting relative longitudinal and transverse movement of said tool and a control device actuated by the means for causing I said transverse movement for preventing said longitudinal movement.

13. A mechanism for dressing a plurality of spaced grinding wheels comprising a dressing tool slidably mounted for movement longitudinally and transversely of said Wheels, a series of spaced cam surfaces for guiding said dressing tool across the face of each of said wheels, a follower on said dressing tool, means for urging said follower against said cams, and power means operable automatically in response to said longitudinal movement for lifting said follower and said dresser transversely from-one cam surface to another.

DONALD F. PRICE.

-HAROLD E. BALSIGER.

MELBURN A. HOLLENGREEN. 

